Peripheral devices, such as personal data assistants (PDAs), cell phones and printers, may be powered by internal means, typically by a connection to an internal battery pack, or by external means, such as by a connection to an AC power outlet or a host computer. Some peripheral devices can be powered by both internal and external means. For example, a PDA can be connected to a computer to draw power therefrom. Additionally, the PDA can have its own battery pack as a power supply. If the battery pack needs charging, the PDA can be connected to the computer for this purpose.
A convenient method to power a PDA in a mobile setting involves the use of a laptop computer. If the PDA is running low on batteries in the field, the PDA can be connected to a battery-operated laptop computer for powering. If an AC outlet is available, the computer can be plugged into the outlet and the PDA can be connected to the computer to power the PDA.
To make such a connection between a computer and a peripheral device, appropriate software, known as a device driver, is installed in both the computer and peripheral device to establish and manage the connection. Device drivers can be categorized according to the communication standard to which they adhere. One category of device drivers adheres to the standard known as Universal Serial Bus (USB). Device drivers that are USB compliant are convenient because many personal computers come with a plurality of USB ports.
Another convenient USB feature is that the standard allows for the distribution of electrical power to many peripheral devices. The USB standard allows the PC to automatically sense and deliver the required power to the various devices attached thereto.
In addition, USB “hot-swapping” obviates the need to shut down and restart the PC to attach or remove a peripheral device: the PC automatically detects the peripheral device and configures the necessary software. This feature is especially useful for users of multi-player games, as well laptop PC users who want to share peripheral devices.
Because of these and other advantages, devices and methods that ensure that a peripheral device is USB compliant without adversely interfering with the intended operation of the device are desirable.